This application claims the benefit of GB patent application Serial No. 9927924.2, filed Nov. 26, 1999 and GB patent application Serial No. 00256451.2, filed Oct. 19, 2000, the disclosures of which are incorporated in their entirety herein.
1. Field of the Invention
The present invention relates to a driver-programmable driving mode system for automatic transmissions including the ability to select between automatic and manual transmission modes, a mode for automatically controlling the default start gear ratio on a vehicle, a mode for providing xe2x80x9ccruise controlxe2x80x9d operation of the vehicle, and a mode for providing power take off operation of the vehicle.
2. Description of the Prior Art
Automatic transmission systems for heavy-duty vehicles such as heavy-duty trucks and coaches, and for automobiles, that sense throttle openings or positions, vehicle speeds, engine speeds, and the like, and automatically shift the vehicle transmission in accordance therewith are well known in the prior art. The known prior art transmission systems often use pressurized fluid to frictionally engage one or more members to other members or to a ground to achieve a selected gear ratio. Also known are automated mechanical transmission systems utilizing electric and/or pneumatic logic and actuators to selectively engage mechanical clutches to achieve a desired gear ratio.
Most automatic transmission systems including an automated mode of gear shifting, wherein the gear shifts are determined by a shift scheduling system, are designed so that the automatic transmission system works by default in the automatic shifting mode (i.e., automatic transmission mode). Such systems typically include a manual override, whereby the vehicle driver can select to operate the vehicle in a manual transmission mode (e.g., semi-automatic) requiring the driver to manually select the desired gear ratio. However, the driver is not provided with the ability to choose the default transmission mode, either automatic or manual. Thus, a driver who prefers to operate his vehicle in manual transmission mode must always override the automatic transmission mode. Further, the pre-configured systems do not provide the driver with the flexibility to change the default mode of operation for limited periods of time, whereby the driver would be able to configure the default mode for particular driving conditions.
In accordance with the present invention, a driver-selected driving mode system for automated transmissions includes an automatic transmission system having an electronic control unit (xe2x80x9cECUxe2x80x9d) with internal memory for storing a driver-determined driving preference for manual (e.g., semi-automatic) or automatic shifting. When a semi-automatic mode has been selected by a driver, the driver manually actuates a shift lever to semi-automatically change gears. The system reads the internal memory of the ECU on start up to determine driver transmission mode preference.
Moreover, the driver can select a default preferred start gear ratio so long as the selected gear ratio is one that is acceptable to the ECU. Both the selected transmission mode and the start gear ratio are stored as a start mode when a manually operated selection device is activated for a period of time exceeding a reference period of time.
The driving mode system also includes a switch for toggling between manual and automatic transmission modes, whereby the driver can change shifting preference during vehicle operation. In a preferred embodiment, the automatic transmission control system includes a display screen to inform the driver of the mode in which the vehicle is operating, as well as display an acceptable range of gears ratios for shifting between during operation of the vehicle in the semi-automatic mode of transmission. Further, the driving mode system includes a cruise control and a power take off. If the vehicle is operating in a manual transmission mode upon cruise control activation, the automatic transmission mode will be temporarily invoked while the cruise control is activated. On the other hand, if the vehicle is operating in an automatic transmission mode upon power take off operation, the manual transmission mode will be temporarily invoked while the power take off is activated.